Interventions in the human body are increasingly performed using minimally invasive methods instead of surgical operations. Said minimally invasive interventions, also referred to as interventional procedures, are frequently employed for treating vascular diseases.
In said procedures the first step is to introduce what is referred to as a guide wire, which serves to probe the lumina, e.g. the interior of blood vessels. Via a guide wire of said kind it is then possible to introduce further instruments, such as, for instance, catheters, endoscopes, placement instruments (e.g. for placing stents, balloons, etc.), dilatation instruments or the like, to the desired position. When swapping between a plurality of instruments, such as e.g. a catheter and a placement instrument, the guide wire is usually withdrawn for each change and reintroduced.
This procedure is illustrated in the following using the example of an intervention for treating a myocardial infarction:
Access to a peripheral artery, e.g. in the groin area, is created with the aid of a puncture.
What is referred to as an introducer sheath is then introduced via this access and advanced as far as the area of the aortic arch.
What is referred to as a guide wire is inserted via said introducer sheath and is then used to probe the outlets of the coronary arteries from the aorta. The guide wire is then introduced into the coronary arteries.
A catheter with an inner lumen is then pushed into the coronary artery via the guide wire.
The guide wire is removed and contrast medium injected into the coronary artery via the lumen of the catheter. The course of the coronary vessels is rendered visible by means of simultaneous real-time x-ray imaging, thereby visualizing a possible constriction of the vessels (stenosis, incipient myocardial infarction).
The guide wire is now reintroduced via the lumen of the catheter and advanced to the point in the coronary vasculature at which the constriction was visible.
The following three operating steps are optional:
The lumen catheter is removed and a balloon dilatation instrument is pushed to the constricted point via the guide wire.
The guide wire is withdrawn again.
The balloon introduced into the coronary vessel is inflated up to as high as 20 bar, thus expanding (dilating) the vessel. The pressure is then released again.
The guide wire is reintroduced into the vessel.
The balloon dilatation instrument is withdrawn and removed from the body.
A stent placement instrument is introduced via the guide wire. Said instrument guides a framework (stent) consisting of metal wires to the formerly constricted point and is inflated there (similarly to the previously described balloon dilatation procedure). The stent is detached from the placement instrument and remains in the body. Its function is to prevent a re-narrowing (restenosis) of the vessel.
Stent placement instrument and guide wire are withdrawn from the body.
With reference to the workflow for coronary intervention this example shows that instruments that are introduced frequently have to be changed.
Currently, the instruments are changed manually, the person carrying out the intervention making the appropriate replacement.
In fact there already exist automated methods wherein the instruments are controlled by remote control. An example of this is magnetic navigation, as provided by the company Stereotaxis Inc. (see U.S. Pat. No. 6,015,414). In that case what is termed a “catheter advancing system”, as described in WO 02/089872 A2, is used for advancing the catheter. Here, the person carrying out the intervention, e.g. the physician, is able to control the movement of the instruments in the body of the person to be examined remotely from the control room. However, only one instrument at a time can be used in a catheter advancing system of said kind. Each time the instruments are changed, the person carrying out the intervention must therefore enter the examination room. Considerable disadvantages are associated with this. Apart from the time lost on account of the distance to be covered, other risks also ensue, such as e.g. a risk of contamination due to the need to change between non-sterile environment and sterile environment.